Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, m;
  cin >> n >> m;
  long long int a[n][m];
  long long int i, j;
  for (i = 0; i < n; i++)
    for (j = 0; j < m; j++) cin >> a[i][j];
  long long int row[n], col[m];
  for (i = 0; i < n; i++) row[i] = *min_element(a[i], a[i] + m);
  long long int f = 0;
  long long int rr[n], cc[m];
  for (i = 0; i < m; i++) {
    long long int mi = INT_MAX;
    for (j = 0; j < n; j++) {
      mi = min(mi, a[j][i]);
    }
    cc[i] = mi;
  }
  for (j = 0; j < n; j++) {
    long long int pre = a[j][0] - cc[0];
    for (i = 0; i < m; i++) {
      if (a[j][i] - cc[i] != pre) {
        f = 1;
        break;
      }
    }
    rr[j] = pre;
  }
  vector<pair<string, long long int>> ans, ans2;
  for (j = 0; j < m; j++) {
    long long int pre = a[0][j] - row[0];
    for (i = 0; i < n; i++) {
      if (a[i][j] - row[i] != pre) {
        f = 1;
        break;
      }
    }
    col[j] = pre;
  }
  for (j = 0; j < m; j++) {
    long long int te = cc[j];
    while (te--) ans2.push_back(make_pair("col", j + 1));
  }
  for (i = 0; i < n; i++) {
    long long int te = rr[i];
    while (te--) ans2.push_back(make_pair("row", i + 1));
  }
  for (j = 0; j < m; j++) {
    long long int te = col[j];
    while (te--) ans.push_back(make_pair("col", j + 1));
  }
  for (i = 0; i < n; i++) {
    long long int te = row[i];
    while (te--) ans.push_back(make_pair("row", i + 1));
  }
  if (f)
    cout << "-1";
  else {
    long long int mm = (ans.size() < ans2.size()) ? 1 : 0;
    if (mm) {
      cout << ans.size() << "\n";
      for (i = 0; i < ans.size(); i++)
        cout << ans[i].first << " " << ans[i].second << "\n";
    } else {
      cout << ans2.size() << "\n";
      for (i = 0; i < ans2.size(); i++)
        cout << ans2[i].first << " " << ans2[i].second << "\n";
    }
  }
  return 0;
}